Optimization of callus induction medium for Hymenocallis littoralis (Melong kecil) using root and bulb explants

Callus was initiated using bulb and root explants of Hymenocallis littoralis on the Murashige and Skoog (MS) basal media supplemented with various auxins, namely 2,4-dichlorophenoxyacetic acid (2,4-D), dicamba, picloram, napthaleneacetic acid (NAA) and indole-3-acetic acid (IAA) at various concentrations. Degree of callus formation based on weight was found highest (+++++) in NAA treatment at 2.0 mg/L (93.33%). Dicamba produced the lowest (+) number of callus formation at 3.0 mg/L (13.33%). In terms of physical appearance, callus induced from NAA at 2.0 mg/L produced white yellowish and globular callus and Dicamba at 3.0 mg/L produced white and hard callus. Callus induction from bulb is possible except with IAA. Bulb explants grown on 2.0 mg/L 2,4-D and Dicamba formed callus after 11 days, followed by 3.0 mg/L picloram, as well but only 9 days for 2.0 mg/L NAA. Degree of callus formation was found to be the highest (+++++) in 2,4-D at 2.0 mg/L (93.33%). Picloram and NAA produced the lowest (++) callus formation at 3.0 and 2.0 mg/L (40.0% each). In terms of physical appearance, callus induced from 2, 4-D at 2.0 mg/L showed yellowish, and soft globular callus. Picloram at 3.0 mg/L produced white yellowish and soft callus; meanwhile, NAA at 3.0 mg/L produced small callus appearance of white and yellowish colour. The callus induction protocol developed in this study provides a fundamental investigation of bioactive constituents from the H. littoralis medicinal plant.   Key words: Hymenocallis littoralis plants, callus induction, auxins, bulb explants, root explants.